Counterbalance

Whenever an opponent casts a spell, you may reveal the top card of your library. If you do, counter that spell if it has the same mana value as the revealed card.

Whirlwind of Thought

Whenever you cast a noncreature spell, draw a card.

Displacement Wave

Return all nonland permanents with mana value X or less to their owners' hands.

Semblance Anvil

Imprint — When this artifact enters, you may exile a nonland card from your hand.
Spells you cast that share a card type with the exiled card cost {2} less to cast.

Elsha of the Infinite

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
You may look at the top card of your library any time.
You may cast noncreature spells from the top of your library. If you cast a spell this way, you may cast it as though it had flash.

Etherium Sculptor

Artifact spells you cast cost {1} less to cast.

Kykar, Wind's Fury

Flying
Whenever you cast a noncreature spell, create a 1/1 white Spirit creature token with flying.
Sacrifice a Spirit: Add {R}.

Scroll of the Masters

Whenever you cast a noncreature spell, put a lore counter on this artifact.
{3}, {T}: Target creature you control gets +1/+1 until end of turn for each lore counter on this artifact.